How To Make Saltpeter

Saltpeter (Potassium Nitrate), or black powder, is an ancient recipe used for gunpowder or dynamite. It forms naturally, and is easy to make with the right ingredients. Recipes for it have been around for centuries, but be aware that the process can be smelly and dirty. Here’s how to make saltpeter:

Mix the manure and other ingredients. Place the cow manure or planting soil in a large pile on top of a tarp. Mix in an equal quantity of green plant life, burned thistles, and wood ash. This large pile should be about 6 feet tall.

Cover the mixture. Place a tarp over the top of the pile, and secure with cinder blocks or similarly heavy objects to ensure that no rain is able to get in.

Let it sit. Every week, uncover and pour stale cow urine (lant) over the pile. Let it sit for about three to four months, repeating this process every week. Stop when you see yellowish crystals forming on the top of the pile.

Scrape the crystals. Once the potassium nitrate crystals have grown to be several inches thick, scrape off the top layer. Keep repeating this process, harvesting more crystals each time. The process may continue to produce crystals for some time. Place these crystals in one 5-gallon bucket, and wait until the crystals stop growing before proceeding in the saltpeter process.

Treat the leftover dirt. Once all the crystals have been harvested, poke holes in the bottom of the second 5-gallon bucket, and place a paper (non-charcoal) filter on the bottom. Then fill the bucket three-quarters high with the leftover pile. Pour boiling water over the mixture, and collect the liquid in a pan under the bucket. Continue this process until the pile is gone.

Evaporate to leave saltpeter. Pour the liquid into open containers once all has been collected. When it evaporates, the particles that are left are potassium nitrate, or saltpeter.

Although homemade saltpeter is easy to make and inexpensive, it is always best to purchase it from an authorized source if you plan to use it, especially in large quantities. Be very careful when dealing with the saltpeter, and keep it away from sparks or other sources of ignition.